Linear rolling bearing

ABSTRACT

In a linear rolling bearing comprising a guide rail ( 1 ) and a guide carriage ( 2 ) that partially surrounds the guide rail ( 1 ) and is supported for sliding through rolling elements ( 3 ) on two long sides of the guide rail ( 1 ), the rolling elements ( 3 ) being arranged on each of the two long sides in at least two parallel, endlessly re-circulating rows ( 4, 5 ) of rolling elements ( 3 ) while a spacer ( 6 ) is inserted between every two successive rolling elements ( 3 ) of a row ( 4, 5 ), on each long side of the guide rail ( 1 ), a common spacer ( 7 ) for both rows ( 4, 5 ) is inserted between every two adjacent rolling elements ( 3 ) of the one row ( 4 ) and between every two adjacent rolling elements ( 3 ) of the other row ( 5 ).

FIELD OF THE INVENTION

[0001] The invention concerns a linear rolling bearing comprising aguide rail and a guide carriage that partially surrounds the guide railand is supported by rolling elements for sliding on two long sides ofthe guide rail, the rolling elements being arranged on each of the twolong sides in at least two parallel, endlessly re-circulating rows ofrolling elements while being guided by spacers that are situated in saidtwo rows between the rolling elements.

BACKGROUND OF THE INVENTION

[0002] Linear bearing guides are known in which the rolling elements areguided by separate, inter-connected chain links. These re-circulatingchains are configured as pull chains. It is also known from a number ofpatent publications that such a pull chain can be configured as an openor a closed chain. Furthermore, there already exist several patentapplications that describe a pull chain not only for a single row ofrolling elements but also as double sprocket chains for twore-circulating rows of rolling elements. One such construction isdisclosed in the publication EP 0 845 611 A1. This shows a linearrolling bearing of the initially cited type in which an open chain isused on each long side of the guide rail as a guide for two endlesslyre-circulating rows of balls. Each chain comprises in its central regionsituated between the rolling element rows, a flexible connecting stripon whose long sides spacers are arranged spaced behind one another.Rolling elements configured as balls are arranged in the spaces betweenthe spacers. This construction therefore results in the formation of adouble row ball chain. However, this chain has drawback that theindividual chain links can rupture easily.

OBJECTS OF THE INVENTION

[0003] It is an object of the invention to provide a linear rollingbearing that is silent in running and possesses a high level ofoperational safety.

[0004] This and other objects and advantages of the invention willbecome obvious from the following detailed description.

SUMMARY OF THE INVENTION

[0005] According to a first proposal, the invention achieves the aboveobjects by the fact that on each long side of the guide rail, a commonspacer for both of said two rows is inserted between every two adjacentrolling elements of a first of said two rows and between every twoadjacent rolling elements of a second of said two rows. According to asecond proposal, the invention achieves the above objects by the factthat on each long side of the guide rail, every two adjacent rollingelements of a first of said two rows and every two adjacent rollingelements of a second of said two rows are guided in a common spacer forboth of said two rows. In this way, chains can be dispensed with, sothat the drawback of rupture of the chain links is eliminated.

[0006] The features proposed by the invention make it possible to obtaina high degree of reliability. Due to the fact that the spacers of theinvention act as double sprocket spacers that are guided by the rollingelements and not, as is the case with pull chains, in separate channelsprovided for link plates, less friction occurs and thus also lessfriction loss. Since the invention does not require link plates, it isalso possible to reduce design space.

[0007] In their regions situated between the two parallel rows ofrolling elements, the spacers may comprise a V-shaped notch into which aretaining bar fixed on the guide carriage adjacent to each long side ofthe guide rail can engage. The rolling elements guided by a spacer canbe enclosed over a larger portion of their circular periphery by thematerial of the spacer.

[0008] A plurality of spacers can be manufactured as plastic parts inthe form of a single composite structure by injection molding, a common,thin connecting web that can be easily torn off being formed on everytwo successive spacers. In the region of rolling element osculation, oneor more spacers may comprise pockets that can be used as lubricantreservoirs. The spacers may also be made out of a porous material thatstores and continuously releases lubricant.

[0009] Examples of embodiment of the invention are represented in thedrawing and will be described more closely in the following.

BRIEF DESCRIPTION OF THE DRAWING

[0010]FIG. 1 is an end view of a linear rolling bearing of theinvention, also showing a partial cross-section;

[0011]FIG. 2 is a side view of the linear rolling bearing, also showinga partial longitudinal section;

[0012]FIG. 3 is a detail showing two parallel rows of rolling elementswith two spacers, in a vertical section;

[0013]FIG. 4 is a view of a spacer as seen in the direction of the arrowIV of FIG. 3;

[0014]FIG. 5 is a detail showing two parallel rows of rolling elementswith three spacers modified with respect to FIG. 3, in a verticalsection;

[0015]FIG. 6 shows the upper row of rolling elements of FIG. 5 with thespacers, in a vertical section;

[0016]FIG. 7 shows the rolling element rows of FIG. 5 with the spacerscomprising lubricant pockets.

DETAILED DESCRIPTION OF THE DRAWING

[0017] FIGS. 1 to 4 show a guide system in end and side views. A guidecarriage 2 is slidingly supported on a guide rail 1 by rolling elements3. The guide carriage 2 contains a total of four re-circulating rollingelement rows 4 and 5. In the sectional view, only two of these rollingelement rows 4 and 5 of one side are represented. The rolling elementrow 4 is the upper row whereas the rolling element row 5 is the lowerrow. The system represented in FIG. 2 has a symmetric construction. Therolling elements 3 in the present case are configured as balls. However,it is conceivable to use rolling elements of any other geometric shape,for example, barrel-shaped or cylindrical rollers. The guide rail 1, onwhich the guide carriage 2 can slide in axial direction is configured asa profiled rail. Sliding is made possible by the rolling of the rollingelements 3 on the guide rail 1 and on the guide carriage 2.

[0018] During axial displacement, the rolling elements 3 circulate inthe guide carriage 2. If no spacers were provided, the rolling elementscould knock against one another during the displacement of the guidecarriage 2 and thus produce noises. To prevent such a production ofnoises, the rolling elements 3 are separated from one another by spacers6. Each spacer 6 is configured so as to simultaneously separate tworolling elements 3 of the upper row 4 and two rolling elements 3 of thelower row 5 from one another. Such a spacer is represented in FIGS. 3and 4.

[0019] A further embodiment of a spacer 7 is shown in FIGS. 5 to 7. Inthis case, two rolling elements 3 of the upper row 3 are connected totwo rolling elements 3 of the lower row 5, so that a total of fourrolling elements 3 are arranged on each spacer 7. Further, this spacer 7is configured so as to surround the rolling elements 3 to the extentthat they cannot fall out. A plurality of spacers 7 are arranged in arow behind one another and are in contact with one another through theircontact surfaces 8 as shown in FIG. 5.

[0020] In the side view of the spacers 6 (or 7) shown in FIG. 4, aV-shaped notch is to be seen that serves to retain the spacers and as anadditional guide groove for a retaining bar 10 also provided in theguide carriage 2. This retaining bar 2 can be seen in FIGS. 1 and 2. Asan alternative to the notch 9 shown in FIG. 4, a notch of any othershape may also be implemented. The retaining bar 10 is connected withboth its ends to the ends of the guide carriage 2. The retaining bar 10is arranged between the rail 1 and the spacers 6 of the rolling elementrows 4 and 5.

[0021] If the guide carriage 2 is removed from the guide rail 1, theretaining bar 10 prevents the spacers 6 (or 7) and the rolling elements3 from falling out of the guide carriage 2. The rolling elements 3,configured as balls, are surrounded by the spacers 6 and 7 so that theycannot fall out. The retaining bar 10 can be made of plastic or wire orany other suitable material.

[0022] To simplify mounting, the spacers 7 made by injection molding canbe interconnected by a thin connecting web 11 as illustrated in FIG. 6.However, this connection should be so thin, that the connecting webs 11tear open after a few circulations of the rolling element rows 4 and 5so that the spacers 7 are then separated from one another.

[0023] As shown in FIG. 7, in the region of rolling element osculation,the spacers 7 can additionally comprise pockets 12 that act as lubricantreservoirs. It is also conceivable to make the spacers 7 of a porousmaterial that stores lubricant and supplies it continuously to therolling elements 3.

[0024] The advantages that can be obtained with the invention are asfollows.

[0025] The spacers are guided by the rolling elements. Conventional pullchains require a separate guide channel for guiding link plates; thisincreases the friction surface and thus also the friction resistance.The use of spacers therefore reduces friction.

[0026] Besides this, conventional pull chains can tear apart as a resultof dirt accumulation and under high accelerations, so that operationalsafety is considerably reduced. The use of spacers endows the systemwith a much higher operational safety and reliability.

[0027] Finally, design space requirement is also reduced because linkplates are dispensed with.

What is claimed is:
 1. A linear rolling bearing comprising a guide railand a guide carriage that partially surrounds the guide rail and issupported by rolling elements for sliding on two long sides of the guiderail, the rolling elements being arranged on each of the two long sidesin at least two parallel, endlessly re-circulating rows of rollingelements while a spacer is inserted between every two successive rollingelements of a row, wherein, on each long side of the guide rail, acommon spacer for both of said two rows is inserted between every twoadjacent rolling elements of a first of said two rows and between everytwo adjacent rolling elements of a second of said two rows.
 2. A linearrolling bearing comprising a guide rail and a guide carriage thatpartially surrounds the guide rail and is supported by rolling elementsfor sliding on two long sides of the guide rail, the rolling elementsbeing arranged on each of the two long sides in at least two parallel,endlessly re-circulating rows of rolling elements while being guided byspacers that are situated in said two rows between the rolling elements,wherein, on each long side of the guide rail, every two adjacent rollingelements of a first of said two rows and every two adjacent rollingelements of a second of said two rows are guided in a common spacer forboth of said two rows.
 3. A linear rolling bearing of claim 1, wherein,in a region situated between the two parallel rows of rolling elements,each spacer comprises a V-shaped notch into which a retaining bar fixedon the guide carriage adjacent to each long side of the guide railengages.
 4. A linear rolling bearing of claim 2, wherein, in a regionsituated between the two parallel rows of rolling elements, each spacercomprises a V-shaped notch into which a retaining bar fixed on the guidecarriage adjacent to each long side of the guide rail engages.
 5. Alinear rolling bearing of claim 2, wherein the rolling elements guidedby a spacer are enclosed over a larger portion of a circular peripheryby a material of the spacer.
 6. A linear rolling bearing of claim 2,wherein a plurality of spacers are manufactured as plastic parts in formof a single composite structure by injection molding, a common, thinconnecting web that can be easily torn off being formed on every twosuccessive spacers.
 7. A linear rolling bearing of claim 2, wherein, ina region of rolling element osculation, at least one spacer comprisespockets that can be used as lubricant reservoirs.
 8. A linear rollingbearing of claim 1, wherein the spacers are made of a porous materialthat stores and continuously releases lubricant.
 9. A linear rollingbearing of claim 2, wherein the spacers are made of a porous materialthat stores and continuously releases lubricant.